The general objective of the proposed University of Guam Marine Laboratory MBRS program, Biomedical Research on Coral-Reef Organisms of Guam, is to provide opportunities for the faculty and talented minority students to conduct biomedically significant research utilizing the ecologically diverse and rich tropical marine environment of Guam and the western Pacific. The proposal includes three research projects submitted by regular principal investigators, a research project submitted by an associate investigator, and a well-structured enrichment component. The first proposal will continue the search for a better understanding of the ciguatera fish-poisoning problem that is prevalent in the tropics including Guam. Specifically, this research will examine the distribution of the benthic dinoflagellate Gambierdiscus toxicus, its microhabitat specificity, seasonality, and population dynamics. The second project will involve studies of the prevalence and distribution of pathogenic bacteria in sediments and reef habitats around Guam. The third project will study reproductive biology of corals with an emphasis on genetic mechanisms. Finally, an associate investigator project will focus on biomedically active natural products in coral-reef invertebrates. Through the proposed activities, the student and faculty research environment will be enhanced. Faculty and students involved in research activities will interact with scientists in the mainland U.S. and they will have the opportunity to learn new techniques and developments by participating in off-campus conferences and research activities as well as on-campus seminars, workshops, and informal discussions by visiting scientists. In the geographically isolated location of Guam, such experiences are especially valuable to the students when making decisions on postgraduate careers.